Stir milk, feta, egg, tomato paste and olives into the onion mixture. Make a well in the dry ingredients; add the wet ingredients and stir until just combined. Fill the prepared muffin cups two-thirds full.

5

Bake the muffins until lightly browned, 13 to 15 minutes. Cool in the pan for 5 minutes before turning out onto a wire rack. Serve warm or at room temperature.